When tuning via logs, should I use the the logged AFR's for a partucular rpm as the guide to make adjustments to my map? The reason I ask is because I think that the AFR readings registered for any rpm may be AFR for an earlier rpm level since it takes time for exhaust gas to reach the sensor. Also I think sensor location(houw far from the engine) would also determine this.

What are your thoughts on this, and how do you guys interpret the AFR logs. I use the LC1 System sampling at 1/12 per second. Should I assume logged AFRs for 5000rpm at WOT is actually the reading for say 4800rpm?

 

Yes there are sample rate issues. All the devices sample both at different rates and at different times (no 'clock'). But the damn delays are usually small enough that you don't have to really take them into account.

 

just a quick comment...

1/12 of a second = .08334 seconds. An engine at 6000 rpm is at 100 revolutions per second.

so for each 1/12 of second engine makes 8.3 revolutions, which is 8 combustion cycles (1 combustion per eccentric shaft revolution (I think that's right?)

So your sample that was just on your gauge for 1/12 (if your display has that quick of response time) of a second was for previous 8 combustion cycles.

Or if you could consider the speed or velocity of the exhaust(variable depeding on RPMs), and measure the distance from the exhaust port and actually figure it out. But, thats only the sampling, what about the time it takes for the signal to get from the sensor to the controller then to your gauge then for your eyes to process it... j/k.

I consider it real-time.